Hardware Outline Character Rasterization

Marc Morgan, Roger D. Hersch

Proceeding of the 6th Eurographics Workshop on Graphics Harware, Vienna (1991) to be piblised by Springer Verlag

For several years, engineers and typographers have been working on a new generation of fonts. The old bitmap description of a character is giving way to characters defined by their outlines. This new description of a character makes a font independent of the size of the desired bitmap character. This in turn makes the font independent of the resolution of the hardware which will be used to render the text.
Studies undertaken at the Peripheral Systems Laboratory (LSP) at the Swiss Federal lnstitute of Technology (EPFL) have led to an algorithm for the rasterization and filling of outline characters. This algorithm is the base of an intelligent font rasterization program [Hersch89]. The fonts are given by outlines described by cubic Bézier splines and by line segments. The quality of the resulting black and white bitmaps depends on two important aspects of the program: the sub-pixel precision used during the rasterization and an appropriate control of the phase of the contour relative to the pixel grid.

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